


The Tides; These Crashing Waves

by creepy_crawly



Category: ATEEZ (Band)
Genre: Alternate Universe, Blood and Violence, Interspecies Relationship(s), M/M, MerMay, Merpeople, Sirens, Worldbuilding
Language: English
Status: Completed
Published: 2020-05-31
Updated: 2020-05-31
Packaged: 2021-03-03 08:41:26
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 18,520
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24468133
Author URL: https://archiveofourown.org/users/creepy_crawly/pseuds/creepy_crawly
Summary: MerMay 2020“Come on, Mingi,” Hongjoong teased, doing a little hopping, wriggling dance to get into his wetsuit. It wasn’t cold enough yet for a drysuit, not late enough in the season, but still, even the notoriously free diving Hongjoong was suiting up.From Mingi’s perspective, that did not bode particularly well for the water temperature, or the diving experience as a whole.
Relationships: Choi San/Jung Wooyoung, Kang Yeosang/Song Mingi, Kim Hongjoong/Park Seonghwa
Comments: 36
Kudos: 159





	The Tides; These Crashing Waves

**Author's Note:**

> Written for MerMay 2020. Originally intended as a short one-shot. That idea sank about 5,000 words in, and, 18k+ later, here we are.

“Come on, Mingi,” Hongjoong teased, doing a little hopping, wriggling dance to get into his wetsuit. It wasn’t cold enough yet for a drysuit, not late enough in the season, but still, even the notoriously free diving Hongjoong was suiting up. 

From Mingi’s perspective, that did not bode particularly well for the water temperature, or the diving experience as a whole. “Hyung,” he tried, “shouldn’t I stay up here? Monitor communications and stuff? Keep an eye on the tank monitor?”

“Nice try,” Hongjoong said, grinning at him. “But that’s actually what the Institute pays Yunho for, and you know it.”

“Did I, though?” Mingi asked. “I’m just an intern, hyung.”

That got an actual snort from both Hongjoong and Yunho.

“Just an intern, my ass,” Hongjoong said brightly. “Your research is excellent, your communications and essays wonderful, and I know for a fact you have the necessary dive skills. Even if you are being a wuss about the water temp.”

Yunho interrupted there. “To be fair, Hongjoong-hyung, this is one of the northern pods. Mingi cut his teeth on tropical pods, like Sana’s.”

Hongjoong just shook his head. “Gotta learn sometime. Come on, Mingi. Your wetsuit can more than handle this, I promise.”

“He’s not actually wrong,” Yunho said, nodding towards where Mingi’s cold-water wetsuit was hanging. “He’s wearing one, I know, but mostly because the pod-head is a brutal mother hen who refuses to talk to him unless Hongjoong is, and I quote, adequately suited.”

“And ‘cause Wooyoung pouts when San hits on me,” Hongjoong added cheerfully, checking their air tanks.

“Wooyoung pouts when San hits on you?” Mingi asked, giving in and starting to work his way into his own wetsuit. 

Yunho all but cackled, settling himself comfortably on the bench by the monitor station. He started checking his monitors, making sure everything was communicating clearly and properly. “Oh, yeah,” he said, grinning at the flush rising in Hongjoong’s cheeks. “We haven’t quite filled you in on this pod yet, have we? So, first things first, Seonghwa is–”

“Going to be meeting us pretty soon,” Hongjoong cut him off. “I told him about Mingi’s interest in childrearing in merclans and differences across pods, so he’s going to take us to the kelp forest.”

Mingi perked up, starting to work on getting all his gear situated even more quickly. It was rare for merpeople to talk about their young, let alone let researchers close enough to see them before the young were juveniles. That Hongjoong had gotten access to the kelp forest, a northern pod’s equivalent of a nursery…

He suspected that Yunho’s original statement had been going to end “head over heels for Hongjoong.”

–––

Correction, Mingi realised, watching his mentor and the pod-head interact. Yunho hadn’t been planning to say that Seonghwa was head over heels for Hongjoong, except maybe as an afterthought to the reality that Seonghwa was, apparently, the love of Hongjoong’s life.

He’d been a little surprised that Hongjoong had chivvied them into the water with the speed that he did; mers weren’t particularly known for keeping exact time the way humans did. They relied on relational time, after all, dependent on a mix of light and tides and an inborn sense of time moving.

But that mystery had been solved when the two humans had made it to their meeting place, as marked by GPS. They hadn’t been the first ones there; a long-tailed, muscular male mer was waiting, flukes flipping gently to keep him in place.

Seonghwa, as he was introduced, was a good eight feet long, top of the head to the tip of his flukes, if Mingi had to guess. His tail was thick and muscular, with the moon pale skin of his torso blending into equally-moony scales running down the front. Those faded into pale, then dark, then darker shades of blue, spotted here and there with a bright paleness. His pelvic fins were dark, ribbons of deep-sea water curling around the paleness of his hips. His back, when he twisted to swim towards them, turned out to have the same deep dark blue running up to nearly the nape of his neck. His long, dark hair was braided back, letting the frills of his ears and the barest hint of his fluttering gills be seen.

But his colouring – while unusual, and gorgeous – wasn’t the surprise.

The dive watch was.

Mingi shot a sideways glance at Hongjoong, who had the grace to look away briefly.

Seonghwa didn’t pay their little aside any attention; he was on them in seconds, flashing razor sharp teeth in what humans would have called a grin and…

And wrapping himself around Hongjoong, nuzzling against his neck, blowing perfectly spherical bubbles against his ears and through his hair, twining them together so that the majority of Hongjoong’s body was supported by Seonghwa’s own, his legs tossed across that length of powerful tail.

_ Holy shit, _ Mingi realised, grateful that his limited fluency in the language spoken by the northern merpods meant he was wearing a full face mask, and couldn’t just lose his respirator.  _ No wonder Hongjoong’s spent so long with this pod. _

He froze, suddenly, pinned in place by the mer’s implacable, silver stare. While what Seonghwa’d worn as he approached them could have been a mimic of a smile, a mimic of human behaviour, what he was currently shooting Mingi’s way was definitely a predatory threat display.

“Stop that,” Hongjoong said, the clicks and rumbles of sound he made translating through the vocalising collar he’d put on before diving in. He also slapped a fin – yellow rubber – against Seonghwa’s tail. “He’s my intern.”

“He’s human. Completely human.”

Oh, that was interesting. Seonghwa was wearing a collar, too. And one of the little earpieces that let you hear the translation, if you were above water or just didn’t speak mer. 

“And I wouldn’t have had you come meet him if I didn’t trust him,” Hongjoong said, now baring his own teeth – flat and human – at the larger male. “He’s not a threat, Hwa. Not to your claim, and not to your pod.”

“And my nesting grounds?” Seonghwa asked, still staring at Mingi.

“Definitely not a threat to your nesting grounds,” Hongjoong said. “We talked about this, remember? I’ve seen Mingi with his own niblings. He’s a good adult. His pod trusts him with their youngest.”

Seonghwa huffed, twisting so that he could both keep an eye on Mingi and soothe the clearly-frustrated Hongjoong. “Humans don’t pod. I’m not stupid.”

“No, but you’re acting like you’ve never spent time with a human,” Hongjoong said. “You tolerate San in your pod, in your nesting grounds, around me. Trust me; you can tolerate Mingi.” He waved the hesitant intern closer.

Watching Mingi carefully inch closer, Seonghwa said, “San knows I will slaughter him and use his bones to adorn you as you deserve if he so much as scratches you.”

Hongjoong grinned, then, popping his respirator out, pressed a kiss to the side of Seonghwa’s head, near one of his frilled ears. “Trust me,” he clicked out, taking advantage of the respirator being out to truly vocalise, “Mingi knows that, too.”

Mingi nodded quickly, even as some quick mental math was putting a series of ones together and coming up with an intriguingly large number. He couldn’t  _ imagine _ the shit storm that would have erupted if more people knew about something like what was happening right in front of him. Before he could stop himself, he blurted out, “ T ell me Yunho scrubs the tapes.”

After the momentary pause – letting the translator take over, clearly filtering back through the earpiece he was wearing – Seonghwa closed his mouth and let his eyes flick shut, the nictating membrane flickering back and forth a few times. The mermish equivalent of approval, of laughter. Of a smile.

Hongjoong was more flushed. “It’s digital,” he protested.

“And Yunho knows to listen but not start recording until he gets the go-ahead,” Seonghwa said, blinking again. “And we don’t bother with these,” he waved a hand at the translators and earpiece, “if it’s just us. Hongjoong’s father’s people speak like they’ve got rocks in their throats, but I’ve polished most of that accent off him.”

And, okay, Mingi thought he could feel his heart stop right there. He’d added up the flirtation and the communication and come up,  _ Hongjoong’s not researching this pod he’s basically married into it he has a thing for the pod-head who has a thing for him and they’re, like, married or whatever _ which was intriguing on a number of levels, starting with the male-presenting pod-head, but…

Hongjoong brought a hand up, tugged a fistful of his own hair, and groaned. A stream of bubbles came up from around his respirator.

Seonghwa’s ears flicked forward, and then back, practically flat to the side of his head. “Ah,” he said. “More than he’d realised.”

“And  _ that _ ,” Hongjoong said, waving at Seonghwa, “is why Yunho waits for the go-ahead. Yes. My father’s father is coldwater mer, and I gather there were some significant concerns about whether Dad’d be born with fins or feet. I was pretty certain to be human-looking, but my father’s family made sure we spent a good part of our summers out on boats, and in the ocean.”

“No wonder you don’t bother with a wetsuit most of the time,” Mingi said, blinking at the pair. “You really don’t care.”

“Still?” Seonghwa asked, pulling back slightly to frown at Hongjoong. “Haven’t we talked about this?”

Hongjoong groaned again.

–––

Being in the water was easily a thousand times better than being on a boat, and that was a thousand times better than being on land, at least by Hongjoong’s estimation. He’d been able to swim before he could walk, and there were parts of his skeleton that really,  _ really _ did not like bipedal locomotion as a method getting around. Dilute d as the blood might have been, there was still some mer there, and some muscles and bones were set up far differently than they likely anticipated.

Swimming was freeing, even if he’d never be as smooth in the water as Seonghwa was. Too much human in him for that. The first time he’d seen diagrams of mer musculature and skeletons next to human, a lot of things started making a lot more sense.

Going in to mer research and mer-human relations had been a no-brainer, though he’d worried a fair bit about getting found out. Conveniently, at least for him, most people still held by the old (and clearly incorrect) belief that mers and humans couldn’t successfully...interrelate.

Merpeople had caught on a hell of a lot faster, though, unsurprisingly, they’d also proven to be very good at keeping that particular secret. It wasn’t until he’d had a doctorate of his own, and been swimming on his own, that any pod had approached him to ask. And it wasn’t until months after that, after he’d cemented a very strong friendship with the pod’s young adults, that anyone had suggested he might not be the only one.

That he’d never been the only one. His father, either. In fact, there was an entire subset of words in mermish for people born between humans and mers. That his father had been born with human-looking legs was rare, but not unheard of. An explanation of the term “fin-legged” had done a lot to answer questions Hongjoong had always been afraid to ask, and ones he hadn’t thought to ask, like what kind of biking accident had led to the long, thin scars on his father’s legs.

His colleagues had counted his success with getting to know various pods to his ease with mermish, and his ease with mermish and its various dialects they’d attributed to spending summers of his childhood on a boat in known mer territories. In turn, Hongjoong was careful not to speak certain dialects, or use certain phrases, that relied on vocal structures not present in the average human. He also monitored the length of his speech; while his lung capacity definitely erred on the deep-sea side, he kept his mermish phrases short enough that no one ever thought to question how a human could get so much out of a single breath.

Which wasn’t to say that no one had caught on, or caught him out. Eden, his PhD advisor, had quickly figured it out once he started seeing records of Hongjoong’s research. Rather than turn his lab slave into a lab rat, however, he’d worked with Hongjoong, helping him polish his research and work towards his doctorate, as well as hide his differences a little more smoothly, so that even another expert would struggle to see anything amiss.

Yunho had caught on, too, though rather less deliberately than Eden. No, Yunho had been reviewing the recordings Hongjoong had been taking during his dives, and had heard semi-familiar vocalisations. Running it through the translator had revealed the song Hongjoong had been absentmindedly singing off and on for weeks, and bringing it to Hongjoong’s attention hadn’t gotten the laugh of cross-cultural contamination he’d expected, but rather panicked silence.

Yunho had proven to be a good friend, and a good ally. He had no qualms with not recording one hundred percent of Hongjoong’s dives, protocol be damned, and he’d been known to experience “technical difficulties” if something got said that shouldn’t be. He also helped spread ridiculous rumours about how Hongjoong had built his tolerance for the cold, or how he practiced his mermish, or how he trained in underwater muscle strength.

Mingi… Mingi was a surprise. Hongjoong had fully expected that he’d never really take on an intern or a research partner, too worried that they might expose the truth. Instead, his work with interns and other researchers was done in labs and through communications and pooled research, not field work together. 

But Song Mingi had come into the lab the first day with the kind of bright grin that Hongjoong couldn’t ignore, and his work with some of the institute’s inhabitants, which ranged from siphonophores to the marine equivalent of primates, had shown him to be kind, caring, and empathetic. He had a good sense of humor, was responsible, and clearly loved his family. Seeing him with his sister’s children, who he called his niblings, had just about melted Hongjoong dead away.

What had really cemented Hongjoong’s decision to see if Yunho was down with bringing Mingi on the boat was how the tall man interacted with Setta.

Setta was one of the lab’s oldest mariprimates, nearly 45 years old. She’d been born and raised in captivity, but retired to the Institute of Sentient Marine Research when she’d been 30 or so. She had a huge tank, complete with other, less complex mariprimates, fish, and general sealife, and a small area well-hidden by various plants and build materials. Her hands – because her dorsal fins were very nearly hands, somewhat akin to what otters had – were not dexterous enough for human sign language, and her species didn’t have nearly as analogous a vocalisation set as mers.

But Setta had a communication board, and the researchers who had started working with her when she had come to the Institute had found her a quick learner and a ready communicator. Magazines had compared her to Koko the gorilla, and maybe it was true, to a degree. Setta was a link between merpeople and the other beings in the ocean, the ones who had gone the path of humanoid evolution, not bigger-is-better. 

Mingi, studying whale song, had heard that Setta liked the sounds. He’d asked permission from her team to talk to her, and, upon seeing on her communication board that yes, she’d like to listen to his whales, please, had gone about getting a hydrophone so that he could share. Setta clearly enjoyed the sessions, and the team had relaxed enough that Mingi could often be found on the decking near the top of her tank, legs dangling in, listening on headphones to whatever the hydrophone was playing down below. He didn’t even jump anymore when Setta bobbed up beneath him, tickling the soles of his bare feet.

Setta wasn’t quite sentient enough to not be considered an animal, not quite humanoid enough, and she was still considered a minor risk to human safety, even if just because she didn’t completely grasp the limits of how humans were more fragile than her. But Mingi didn’t let that stop him from treating her kindly. He wore a floatvest and never went above her tank without letting someone know, and he always asked her permission before sticking his feet in the water. He bowed to her in greeting and when he left, called her ‘Setta-halmeoni,’ and spoke to her the way a polite Korean boy should speak to his elders. He learned to use her communication board, and talked to her, often forgetting to record their ‘conversations’, to the frustration of her research team.

She wasn’t human, but Mingi didn’t seem to care.

And Hongjoong cared about that.

–––

Before Seonghwa had even  _ thought _ of agreeing to Hongjoong’s idea, to inviting a human out to meet him, meet his pod, see where they  _ lived _ , he’d made Hongjoong talk. And talk. And talk some more. There had been a lot to talk about, after all. Seonghwa needed to know who this person that Hongjoong trusted was, and why Hongjoong trusted him, and why Hongjoong thought he should trust him. 

And he hadn’t gone easy on Hongjoong. In fact, Hongjoong had joked, towards the end of their bickering negotiation, that the committee who had questioned him about his thesis had gone easier on him. 

Seonghwa had accepted that with a shrug. He was responsible for the safety and wellbeing of his entire pod; if Hongjoong couldn’t convince him that this person was worthy of a fraction of the trust that he himself had earned, that was all there was to it. And Seonghwa knew that Hongjoong would accept his judgement, on that front. Not only was he a member of Seonghwa’s pod, but any risk to Seonghwa’s secrecy was a risk to Hongjoong’s own. If Seonghwa had said no, he knew that his human would have listened.

Seonghwa, in turn, had listened to Hongjoong. He’d asked constant questions: who was this person? What was he like? What was his background? What was he researching?  _ That _ had piqued Seonghwa’s interest in actually meeting the man; he was a warrior, blooded and scarred, yes, but Seonghwa was also, to his very bones, a nurturer.

Which was, in the end, part of why he had said okay to Hongjoong bringing along another person, and why he’d agreed to show this person to the pod’s nesting grounds. To  _ his _ nesting grounds. He wasn’t  _ really _ second-guessing that decision, now that the three of them were in the water and moving, but Seonghwa could feel little ebbs and surges of nervousness in his belly. This was a risk, perhaps even a greater risk than bringing in Hongjoong. There’d been so much less to lose, then, and Hongjoong had had every bit as much reason to keep their secrets.

_ He’s a good person _ , Seonghwa reminded himself.  _ Hongjoong has taken him in as a friend. He can be trusted. _

Taking a deep breath, so deep that his gills actually flared for a moment, Seonghwa said, “Hongjoong tells me you’re researching alloparenting in pod structures and across clans.”

Mingi flailed for a second, clearly surprised at being addressed. “Uh, yes. Yessir.”

Seonghwa rolled his eyes. Humans were such prey animals, even if they were one of the most destructive predators the world had ever seen. “No need to call me sir; if you call Hongjoong hyung, you can do the same for me. Or not; our clan has never really used human honorific systems, and our pod definitely doesn’t.” He flipped quickly, getting a glance of the human, before straightening back out. “Why are you so interested in childrearing?”

“Uh, well…”

“He’s not gonna eat you, Mingi,” Hongjoong interrupted. “Go on; I know you can talk about this for hours.”

Mingi made an odd noise. “Well, I’ve always found it interesting how differently people raise their children. On land, some communities have maintained alloparenting practices for hundreds of thousands of years, while other communities have gone from common alloparenting to nuclear family groups in the span of a couple of generations. It’s fascinating to see how people reflect the parenting they received, and how they incorporate societal changes. This is especially true across cultures, like when a person from one community starts coparenting with someone from another background. And, given that marine social structures are often overlooked in cultural studies, I thought it would be interesting to learn more about how people underwater think about raising children.”

By the end of his little speech, Seonghwa had turned so that he was swimming backwards, facing the human and listening to him explain. It was, he realised, kind of cute how the man clearly let go of his nervousness when he started talking about the topic of his research. Hongjoong was right, damn him; this was a good kid.

“Well,” he said, giving a strong push with his tail to keep moving steadily, “understand that you’re getting an unprecedented look here, human, and be prepared to entirely attribute it to the fact that Hongjoong has spent years getting to know my pod.” Another strong push. “Oh, and the fact that you’re adorable.”

The expression Mingi made was  _ completely _ worth the effort of pretending that swimming backwards was effortless.

–––

Seonghwa could feel his pod’s gazes, watching as he swam overhead with Hongjoong and an unknown human. Beneath the rocky overhang that San and Wooyoung had cobbled above their odd little cave, he could see the yellow glow of San’s eyes; Seonghwa flicked him a quick hand signal, letting him know that all was well and this visitor was with him. 

The pod grounds themselves were unusually empty and quiet; he had warned his pod that Hongjoong was visiting, possibly with a guest. They’d clearly heeded his warning. It was so starkly quiet, in fact, that he could actually hear the lilt of Yeosang’s voice as he sang to the young, deep inside the kelp forest.

Seonghwa brought them to a halt, just outside the lip of the sound. “Hongjoong knows the rules already,” he said calmly, “but you need to learn them.” He thought it unlikely that Yeosang would let Mingi into the deep tangle of kelp, not on his first trip (and likely not on his fifteenth), but he’d rather be more prepared than less.

Mingi nodded, watching him.

“First,” Seonghwa said, raising one finger, “the kelp beds and the nests within them are fragile. They’re also dangerous. They tangle the unwary.” He let his lips part, revealing his sharp teeth. “If you get caught, do not panic. Quietly ask Hongjoong or I for help. We will untangle you.

“Second. I do mean quiet. You’ve noticed that my ears are very different from your own; theoretically, you’ve learned why. I will tell you know that while I am mostly listening to vibrations in water, sound carries down here. Our young have very sensitive ears, because they need them to keep themselves safe.”

“On that note,” Hongjoong said, reaching down into one of the pouches hanging from his dive belt. He pulled out a couple of small devices. Hanging on to one, he passed the other two to Mingi. “Microbreathers. They have a limited oxygen amount, and a limited degree of rebreathing. No bubbles, no noise.”

“Thirty minutes per microbreather,” Seonghwa said, nodding at the pair Mingi was holding. “Unless you’re Hongjoong, and need half as much oxygen.”

“Unless you’re Hongjoong, who cheerfully lies about how many he uses up on dives,” Hongjoong agreed. He was busily working at the clips holding his tanks to him, wriggling and writhing, so it really should have been no surprise that the small device slipped from his hand.

Seonghwa caught it easily, twining one of the ropes around his throat around it to hold on to the small tube. Then, reaching out, he helped Hongjoong out of his tanks and various dive apparatuses...including his flippers.

Mingi startled as a voice came inside his mask. 

“Surface to dive. You guys reach the nesting grounds?” Yunho asked. “Hongjoong’s monitors just went wild, but you’re not screaming.”

“Yeah,” Mingi said, remembering that they were being monitored. “Hyung’s taking his tank off. I’ll be turning off and removing mine, too.” Then, after a moment’s pause, he added, “we’ve both got two microbreathers. Don’t worry about us until it’s passed an hour.”

“I’ll check in at the half,” Yunho replied. “And, hyung? Stop forgetting to tell me you’re going off leash. Scares the shit out of me, and you know it.”

“Yeah, yeah,” Hongjoong said, the sound somehow conveying the same level of offhanded sarcasm in mermish as it would’ve in Korean. “Stop getting your tail in a twist.”

“Mingi,” Yunho said, clearly pretending to be above Hongjoong’s sass, “when you get to be an old, grizzled researcher, do me a favour and don’t swim around with a partial mask. I hate having to wait for translations of his insults, just because his only recording is the vocotrans.” He paused, the translation echoing out through a speaker on the boat, and then added, “and because some phrases just do not translate well.”

Mingi snorted. “Got it, Yunho. Dive out.”

“Surface out,” Yunho agreed.

Seonghwa and Hongjoong helped work Mingi out of the tangle of equipment he was wearing, then to rebalance his buoyancy by draining the little air-filled float sacks he was wearing. Seeing his look of concern as he bobbed, waiting next to his tank so that he could keep breathing oxygen until the last second – Hongjoong kept flitting back to his own to take another breath – Seonghwa grinned.

With that many teeth, it wasn’t comforting.

“We’ll reinflate them later,” Seonghwa said. “When you get redressed. I can actually exhale air down here, for all that I usually don’t. And if I can’t clear enough gasses for two of you…” His grin widened. “Well, having a siren in the pod is useful, I suppose.”

Mingi dropped the tube connecting his airtanks to his mask’s built in respirator at that. “A  _ siren _ ?!” he managed, trilling out the same pattern of rolling squeaks that Seonghwa had used.

“Oh, seas, your accent is  _ awful _ ,” Seonghwa said, making a face. “No wonder Hongjoong has you in the full mask.”

Hongjoong, who had snagged Mingi’s hose and plugged it with his thumb, sent the mer a reproving look. “I thought we’d agreed to introduce him to San  _ slowly _ ,” he said.

Snatching the tube back from Hongjoong and holding it against the correct connection point, Mingi blew out a large bubble to clear the intake, then said, “let me get this straight. You – a northern mer – include a siren in the census of your pod.” 

“Yes,” Seonghwa said.

“And you let him near your nesting grounds,” Mingi continued, remembering something Hongjoong had said. “And near your chosen partner.”

“Yes,” Seonghwa said again. His tail flipped a little, and then he added, “though I didn’t for a long time. And it’s mostly because of Wooyoung that we let him in in the first place.”

“The one who pouts?” Mingi asked Hongjoong.

“The exact same,” Hongjoong said, nodding. He kicked a little, balancing his lack of flippers with some startlingly long feet, and a casual grip on Seonghwa’s shoulder. “But I’ll introduce you to Woo and San later – and from the boat. I trust San, but…”

“But San doesn’t always trust himself,” Seonghwa said. He looked at Mingi again. “Now, come on. Oxygen off, microbreather in, let’s go.”

Taking a deep breath, Mingi reached down, shut off his oxygen tank, and quickly screwed the first microbreather into place on his mask. He could feel more than hear it hum to life. He turned to look at Hongjoong, who had his microbreather in place, as well. 

At Hongjoong’s thumbs up, Seonghwa twisted, turned, and started guiding both men towards the dark haze of the kelp forest.

–––

Yeosang came slowly through the tangled maze of kelp as he heard his pod-head’s whistle. He’d been keeping the younglings quiet for most of the day, deep in the kelp beds, ready to hide. When he’d felt the swirling current of someone swimming near, he’d stopped singing and sent the children to hide. Seonghwa had told him, just this morning, before he swam out, that he might be bringing guests by. That he might bring them to the nursery beds, and the nesting beds. 

Yeosang trusted Seonghwa, he did. Far more than he had trusted just about any other pod-head he’d known. But there was a reason that he, unmated and unbred, was often left to guard the nesting grounds and the younglings alone. Shifting his sharkskin cape around his shoulders, Yeosang made sure that all of his knives were in easy reach, and that the sheaths covering the blades stitched to his fins were ready to come off at a shrug.

Only then did he part the dark brown curtain and ease into the open waters of the sound.

“Seonghwa,” he greeted, keeping his eyes down. “Hongjoong.” He didn’t greet their other guest; he didn’t know this person, wasn’t sure how to address him, didn’t want to seem kind if he needed to kill him.

His pod-head’s broad hand was warm, a soothing point of contact above the faint lift of his dorsal ridge. He could feel Seonghwa’s pulse, steady and slow, unconcerned. His tail was moving steadily, yes, but in patient, easy motions, barely more than a shifting of muscles to maintain his position and orientation. Seonghwa wasn’t concerned. That was good.

“Yeosang,” Seonghwa said, his voice calm and soothing. “This is Mingi. He’s Hongjoong’s...student?”

“Coworker, more like,” Hongjoong answered, recognising the question as being directed at him. “A bit like a student, though.” 

Seonghwa hummed understanding, the sound rippling through the water around them. “His mermish is worse than Hongjoong’s used to be,” he explained, “so Hongjoong and I will stick very close, to help with translation.”

_ Good _ , Yeosang thought, peeking at the long body of the interloper from the corners of his eyes. More adults, in case something went wrong. Strong swimmers, the both of them, and even if Hongjoong was an obligate surfacer, like Jongho, he could probably hold his breath far longer than this human.

The intruder spoke, his voice weirdly echoing in his plastic face shield. He waved a hand, an all-too human gesture, but didn’t do that thing Hongjoong did,  _ smiling _ . He kept his teeth covered, polite, and maintained a steady gaze on Yeosang’s nose. Probably his nose, anyway; Hongjoong had explained that human sight didn’t work nearly as well underwater as mer did.

“So, uh, Mingi says hello,” Hongjoong translated, turning human speech into familiar vocalisations for Yeosang. “He says that it’s nice to meet you; Seonghwa and I have explained to him that you are a guardian for the young for this pod. He understands that that is a great honor, and an immense responsibility. If you are willing, he’d like to ask you some questions. About your duties, and your thoughts about what the young need, and how to care for them.”

The human said something, directly to Hongjoong this time. A strange look crossed his face, and then he turned back to Yeosang. “He also says. Uh, well, he says if you’re not comfortable with him approaching the kelp beds, he can back further away.”

Yeosang stared at the human in surprise. To get this close to a pod’s nesting grounds, and then to offer to go away…? But maybe the human expected him to follow? To leave the beds unprotected?

“I’m right here,” Seonghwa said, flicking a rush of water Yeosang’s way with a powerful bat of his tail. “I can watch the beds, if you’d like to talk to him.”

Yeosang hadn’t even realised his pod-head had drifted away from him. How had he not noticed? Was he getting that careless?

_ No _ , he told himself firmly.  _ You’re not careless, Sang-ah.  _ He wasn’t, not with the safety of the beds and the younglings. He  _ knew _ that, even if he struggled to remember it. Seonghwa was just that good a swimmer, and that safe a mer in Yeosang’s mind.

After a moment’s hesitation, Yeosang reached up and slipped the bone clasp on his cape. He held on to the sharkskin, even as he found the buckle holding his bandolier of knives in place. Undoing it, he passed the knives to his pod-head. “Be safe?”

“Of course,” Seonghwa promised, not seeming to mind the way Yeosang watched him buckle the knives into place across his own torso. He shifted a little, resettling some of his jewelry around the blades, so that it would be easier to draw them, if he had to, then offered Yeosang a slow, careful wave of his earfins. “We’ll be okay. San’s listening, if he’s needed.  _ WHICH HE’S NOT _ ,” he added loudly.

Yeosang thought he could hear the burble of San’s laughter, bouncing from beneath his rocks.

“Right,” Yeosang said. He inhaled deeply, feeling the cool rush of seawater against his gills and throat, and then turned back to the human and Hongjoong. Seeing the former’s wide eyes, he quickly flicked his sharkskin cape back into place, redoing the bone clasps that would hold it steady while he swam. “You are my translator, Hongjoong?”

“At your service,” the man agreed.

Nodding – to Hongjoong? To Seonghwa? To himself? The seamother only knew – Yeosang gave a powerful kick and swam out towards the human diving in his territory.

–––

Mingi was strangely quiet as they swam back to the boat, not saying a word as he propelled himself through the water with quick, easy kicks. He’d been chatty enough with Yeosang, for all that the conversation had to go through Hongjoong as a translator. With Yeosang’s permission, Mingi had asked Yunho to start recording their communications, since he couldn’t take notes underwater.

Nothing about the interview had been unusual or concerning, on either party’s end. Mingi’s questions had been like they always were: well thought out, respectful, and targeted. He’d given Yeosang room to expound as much or as little as he was comfortable with, and responded easily to what he learned. Yeosang’s answers had gotten longer and more nuanced the more time they’d spent in conversation; Hongjoong was pretty sure that Mingi’s grasp of mer body language was advanced enough that he also could see the mer relaxing as time went on. 

Mingi and Yeosang had parted on good terms, with Yeosang going so far as to promise to think on some of the things Mingi had asked him about, and to follow up with him next time he and Hongjoong came for a visit. He’d even shyly offered to explain the layout of the nursery forest, next time.

They’d wrapped up their visit with a little more time spent with Seonghwa, touring through the pod grounds. Now that Mingi was deemed safe, at least by Seonghwa, various members of the pod had begun to emerge, going about their day to day business. Jongho, fresh back from a trading trip with one of the other local clans, had been delighted to meet “Hongjoong’s human.” Mingi, in turn, had been fascinated by the way Jongho had described his role within the pod. Given that Jongho spoke with enough out-of-clan mers and spoke English and Korean, albeit not particularly well, Hongjoong had had no qualms leaving intern and courier to speak slowly to one another, while he drifted off with Seonghwa for a bit.

While Hongjoong hadn’t had as much information as they’d been hoping to find, Seonghwa didn’t seem to hold that against him in the slightest. Hongjoong knew that, when they’d finally gone off to find his intern, the marks on Seonghwa’s shoulders weren’t going to go unnoticed. He’d been surprised – perhaps pleasantly? – that Mingi had  _ also _ noticed the way one of Hongjoong’s piercings had been swapped out for finely-gilded bone. 

Yes, as quiet as Mingi was on the swim back, Hongjoong knew he was going to be facing a lot of questions when they surfaced. He just wasn’t sure what they would be.

–––

“Ugh, tell me that’s not a fresh one,” was the first thing that greeted Hongjoong as he basically beached himself on the swim platform.

Hongjoong made a face at his friend, already working off various bits of his gear. He lobbed his weights and fins carefully to one side, then helped Yunho help him out of his tangle of tanks and tubing. He had already seen Mingi bob to the surface, pretty close by, and so he made no delay in stripping off the rest of his dive vest and waving his friend closer.

“Come on,” he said, continuing to gesture Mingi in until he could reach out and touch him, if he tried. “Let me help you get some of that gear off.”

Mingi shoved his mask up and off, his wet hair splaying wildly. “All due respect, hyung,” he called back, “get your ass in the boat.”

“I like him,” Yunho commented, already hooking a hand into Hongjoong’s divebelt and hauling him up and over the wall of the boat. “He knows protocol.” He hummed, reaching out a hand to take Mingi’s mask. “He  _ follows _ protocol.”

Mingi made a soft noise at that, wiggling up onto the swim platform. Unlike Hongjoong, he snagged one of the safety cables and hooked it into his divebelt before starting to work on the various accoutrements. He took the mesh bag Yunho offered, dropping his dive weights into it even as he worked on deflating the various floatsacs he’d been using. Those went in the bag, too, and that all went onto the deck. 

Hongjoong watched as Yunho helped Mingi out of his heaviest equipment, then up on to the deck of the boat. Mingi, he noted, was careful to put away his gear in an exact order, his steady movements and quick doublechecks looking nearly ritualistic. Then again, he figured, Mingi’d done his graduate work in the tropics, where there were plenty of siren choruses waiting for the unwary. Well-maintained gear could be the difference between life and death, if it could give your research cohort time to reach you. 

That thought in mind, he made quick work of tidying up his own gear, though it was nowhere near as rhythmic as Mingi’s work. Also, he finally got around to answering Yunho’s question.

“No,” Hongjoong said, checking his flippers for damage before slipping them upright in a bin. “It’s not new.”

“Hyung?” Mingi asked, looking at him curiously.

Hongjoong waved to his ear. “Yunho was asking about my ear. It’s not a fresh piercing.” He flicked a nail against the delicate bit of bone, something warm coiling in his belly at the thought of the work Seonghwa had put into the piece. “Just a repurposed old one.”

“Let me guess,” Yunho said, leaning in and tipping the pile of tanks upright, checking the oxygen levels on each one. “Next time I see Seonghwa, he’s going to be sporting a bit of metal made this side of the water?”

Hongjoong hummed. “I think he’s actually planning on using it for something else. Not sure what, but he didn’t opt for wearing it, so…”

“I’m pretty sure I’ve had this conversation with one of my roommates,” Mingi said, leaning back against the wall of the boat and watching them. “Hwanwoong. Was gonna let his boyfriend pierce his nipple. In our apartment, I might add.”

“Oh, dear,” Hongjoong said. “Did they go through with it?”

Mingi shook his head. “Nah. Geonhak’s an idiot about some things, but he’s not a total moron, so he made Hwanwoong visit him at work to get it done. He does piercings and ‘traditional’ tattoos.”

Yunho raised an eyebrow. “Traditional, huh? Needle and hammer?”

“Needle, mallet, fire, and charcoal,” Mingi agreed. “Same way the ancestors did it. Legal in all of South Korea, regardless of medical license.”

“Amazing how he achieved that colourwork on your hip,” Yunho said, biting back a grin, “with traditional methods.”

“Mm,” Mingi said, his own grin breaking through. “That one was done in the modern tradition. He likes to experiment with styles...all traditional,  _ of course _ .”

Hongjoong shook his head. And people thought  _ he _ was the troublemaker! Turning to Mingi, he said, “ G o ahead and get out of that wetsuit, get a shower. Throw on some dry clothes, then meet me in the galley? We can go over your notes, talk about what you saw. I know you have some questions…”

Mingi nodded. “Got it, hyung. Long as you do the same.” He pushed himself to his feet, already unzipping his suit as he headed towards the stairs. “Hell, I might even leave some hot water for you.”

“Brat!” Hongjoong called after him. He looked at Yunho. “Can you believe what I have to put up with?”

“You encourage it,” Yunho told him. “Not to mention, I’m, like, ninety percent certain Eden would say you deserve it.” He paused, halfway to hefting a tank towards the compressor, then said, “ A ctually, no. Ninety five percent certain.”

He even had the audacity to laugh as he dodged the wet glove Hongjoong tossed at him.

–––

“So,” Hongjoong said, cradling a cup of steaming tea between his hoodie-covered hands.

“So,” Mingi returned, letting himself relax against the wall of the booth. Dives usually left him wiped, and today’s moreso, despite the excitement. Perhaps because of the excitement?

Hongjoong fidgeted. He’d come into the galley in well-worn sweatpants and an oversized pink sweatshirt, hair tugged into a messy apple-tail on top of his head. When he’d sat down, the pink fabric had practically swallowed him, and he’d happily tucked his hands into his sleeves.

While Mingi would normally be internally cooing about how cute his hyung looked, today was… Different. There were bigger things on his mind, and far more confusion than usual. He had questions, so many questions, but no clue where to start. 

“First question that comes to mind, Mingi,” Hongjoong said quietly. “I promise I won’t get upset. I’ve sprung a lot on you today; I can completely understand a social filter going offline for a bit.”

“What the everloving fuck happened to Yeosang?” Mingi blurted out, the words breaching his control nearly as soon as Hongjoong granted him somewhat-sideways permission. “His…” He waved a hand at his own tee-shirt covered chest. “That wasn’t a shark, hyung. Or a seal. Or any non-sentient predator.”

“No,” Hongjoong agreed, shaking his head. “It wasn’t.”

Mingi paused, thinking. “He’s so quiet, but...my god, he had obsidian  _ sewn _ into his ventral fins. And his flukes. His opercula were  _ pierced _ , hyung. One of the most sensitive, most life-critical parts of his body, and he’s  _ weaponised it _ .”

Hongjoong nodded, privately a little glad that Mingi had recognised the poisonous spines thrust through the frilled skin covering Yeosang’s gills for what they were. Many researchers had seen operculum spining and called it decoration, adornment; it was only lately that the ‘weapons’ explanation was gaining ground.

“He’s...what  _ happened _ to him, hyung?” Mingi asked. In his chest, a deep pressure was bearing down against his lungs and throat, like his heart was doing its damnedest to crush the life out of him.

There was a long, long silence. Then, bowing his head over his tea, Hongjoong sighed.

“That’s one of those things I can’t tell you, Mingi,” he said. “Not because I don’t know, but because it’s not my place to tell. And because I don’t know it completely. Because Yeosang’s never told me, and, honestly, I’ve not seen a whole lot of Yeosang. He’s pretty nervy of people who aren’t members of the pod, and even then he sometimes gets spooked and ends up hiding in the kelp beds or with San.”

“With San,” Mingi echoed, “the siren.”

“Yeah,” Hongjoong said. “San’s a siren. A pretty small one, to be fair.”

Almost against his will, Mingi felt himself making an interested noise. “Pray tell,” he asked, “how big a ‘pretty small’ siren is?”

Hongjoong’s grin was definitely guilty. “Ahh, probably about 3 metres, crown to fluke? I’ve never actually taken a tape measure to him, to be fair.”

“Oh, good,” Mingi said, the words distant. “He’s only roughly nine feet of murderous impulses and unspeakably high prey drive.”

“I’ve known him for three years,” Hongjoong offered, “and in that time, he’s not actually killed anyone.” He paused. “Well, I take that back. He’s not killed anyone who didn’t have it coming – which, yes, I realise is nowhere near as soothing out loud as it was in my head.”

This wasn’t real, Mingi decided. Yunho was about to burst in with a camera. Better take it for all it was worth. “I am concerned,” he said, suddenly aware of how strangled his voice sounded, “that there was any universe in which that was considered soothing.”

Hongjoong had the grace to look a little embarrassed. “There was an incursion from a couple of rogue sirens,” he explained. “Seonghwa’s pod is known for being...well, for being eclectic. They thought it would be easy pickings.”

“And that’s who San killed?”

“And Yeosang, yeah,” Hongjoong said, nodding. “He doesn’t wear those knives for fun.”

“And there was me, thinking they were an advertisement of his preferred kinks,” Mingi said, false cheerily. Then, recalling where he was and who he was with, he flushed. “Oh, my god. Forget I said that. Forget I said anything. Let’s blame the whiskey Yunho poured in this tea.”

Hongjoong threw his head back and laughed. “Don’t worry, Mingi, this is entirely off the record. And, uh, yeah, if that’s what you were looking for, I’d advise against asking Yeosang for it. Not that I know anything about his interests.”

“Because you’re a married man,” Mingi said more than asked. Seeing Hongjoong’s look, he beamed. It wasn’t a happy, comforting expression. “I did my thesis on family units in mer society,  _ Doctor Kim _ . I recognise a marital mark when I see one.” He looked pointedly at the dark wood industrial running through the top of Hongjoong’s left ear.

Hongjoong reached up to stroke the engraved wood. “Saw Seonghwa’s, did you?”

“It was a unique adornment when I met you,” Mingi admitted, “but I chalked it up to years of working with mers and the fact that you’re generally accepted as basically having been adopted into this particular pod. But, yeah. As soon as he was close enough that I could see his ears…”

He shook his head. “Anyway, you’re a married man, apparently, with far more mer in you than science thinks is possible.”

“That about sums it up, yeah,” Hongjoong agreed. He toasted Mingi with his tea, then took a noisy slurp. And coughed. “Seamother, you weren’t kidding about the whiskey.”

“I really, really wasn’t,” Mingi said, sipping at his own tea. “But I did see where he put the bottle, if we need to get completely smashed after this conversation.”

Hongjoong paused, mug halfway between his mouth and the table. “Please tell me you’re not about to ask about my sex life.”

“Wha– oh, god, heaven,  _ no _ !” Mingi squawked. “Family units, man, not reproduction! Social science, not pure!” He made a face, trying to unthink the questions that Hongjoong’s comment had brought to light. “No. No, god. No, I want to know more about the pod.”

Raising his mug once more, Hongjoong nodded. “Okay, yeah. That I can do.”

Mingi took a generous slug from his own mug, still disturbed. “Good. Let’s talk about Jongho. How’d he end up in the pod? He’s definitely not blood related…”

–––

“You were making friends with the pretty human,” San purred, curling between the strands of kelp. He was careful to coil above the pattern Yeosang was absentmindedly pressing into the seafloor, conscious as ever of how protective the mer could be.

“Who said he was pretty?” Yeosang asked, raising an eyebrow at the siren. He knew that San’s eyesight was better in the nighttime dark than his own was, but it was a pretty close match, here in the kelp. Even nightsight couldn’t see through the thick strands, and Yeosang knew the ripples and rolls of the weed better than he knew his own biorhythms.

“Not blind,” San answered, drifting a little higher. He whipped the end of his tail around a long strand of kelp, anchoring himself, then let his head and torso sink closer to Yeosang and his busy tail. “I watched from inside my cave.” He fluttered his accessory fins playfully. “Asked Jongho about him, too.”

Yeosang snorted. “You’re being a creeper, San. What does Wooyoung think?”

That got him another cheerful flutter of fins. “Wooyoung thinks I’m ridiculous,” San said airily. “But then, he only half-believes me that you came out of the beds.”

“I’m not  _ that _ much of a loner,” Yeosang said, finally looking up from where he was flipping his tail flukes againsts the seafloor. “Am I?”

San waved a hand back and forth. “A little bit sometimes, less others. Depends on you, you know. And besides.” He released his hold on the kelp, letting himself sink further. “No one minds. Not around here.”

Still not entirely satisfied, Yeosang seized the nearest stalk of kelp and began to pull himself up, until he was high enough that the water moved by his tail wouldn’t disturb his design. “I’m trying to do better,” he muttered, mostly to himself. 

“You are,” San assured him, twining around himself until he, too, was upright. Opening his arms, he waited patiently for Yeosang to huff and lean into the embrace. He’d learned early on that one did not surprise Yeosang with hugs. Not unless one enjoyed new gillslits.

But, given the way Yeosang was leaning against him, he had nothing to fear, here. San closed his arms around the mer, giving him a careful hug that they both knew he could escape at any time. He tucked the mer under his chin, feeling the steady rise and fall of his chest, his heart slowing as he let the anxiety go.

“Give it time, Yeosang-ah,” San said. “And know that I will rend the flesh from the bones of anyone who dares to even think of hurting you. Even if he is Hongjoong’s precious human student thing.”

Yeosang’s giggle wasn’t entirely bright and cheerful, but San counted it a win, anyway.

–––

“Bringing other men into our swing, Sannie?” Wooyoung asked, his voice thick and soft with sleep. Even as he spoke, he raised his arm, letting San tuck the drowsy mer he was carrying against his side.

San watched, satisfied, as Yeosang curled against Wooyoung’s bulk, nestling deeper within the braided kelp-and-rope swing that he and Wooyoung slept in. “Promised him he’d sleep well,” he told his mate. “You know how his nightmares are.”

Wooyoung made a face of understanding, twitching his tail to lay more comfortably over Yeosang’s. He folded an arm over the other mer, covering the sensitive nape of his neck with a broad palm. “Hypnotised him?” he asked.

San nodded. “He asked.”

“Wasn’t an accusation, love,” Wooyoung soothed, watching the discomfort play across San’s features. “I know he asks you for it, sometimes.” His lips tightened. “I also know what it does to you.”

“I’m fine,” San said, shaking his head and curling his tail more comfortably beneath himself. “I have the darkwatch, anyway.”

Making a soft noise, Wooyoung shifted so that he and Yeosang were comfortably entangled in the swing, swaying softly with the ebb and flow of the water. It was how he and San slept, usually, twined together and lulled by the beat of the current around them. He didn’t mind sleeping with Yeosang like this; they’d done it often enough, both he and Yeosang and San and Yeosang and all three of them together. Wooyoung didn’t begrudge his exhausted companion the rest; he just wished there was another way for Yeosang to be fully rested, one which he wasn’t so ashamed to claim. 

“You’ll be careful on watch?” he asked.

San’s answering grin was sharp with more than just fangs. 

–––

“A quiet watch?” Seonghwa asked, kicking forward from the stone outcropping he’d hooked his sleep-rope around. Said rope was in his hands, being twisted up once more so that he could stow it away.

“Indeed,” San said, holding out the string of fish he’d gathered. “So quiet, I was able to lay out the lines for these, entirely uninterrupted. Given how full they are, I’d say the dawn watch was quiet, too.”

“Silent, per Jisung,” Seonghwa said. “He woke me up on his way back in. You must have passed him on your way to gather your lines?”

San shook his head. “We went different ways, if he came through here and woke you. I’d best get these back to the storehouse. People are going to be wanting to eat.”

Seonghwa nodded. Before San could swim past him, though, he lay a hand on the siren’s arm. “San?”

“Seonghwa?”

Seonghwa treated him to a gentle smile. “Before you take those to the stores, let Wooyoung take his pick among them. You’ve a tolerant mate, and he cares about Yeosang, but a little grease can smooth a lot.”

San’s cheeks flushed. “Did he…”

Seonghwa shook his head. “Not a word. He really doesn’t mind, I think, San. But I saw Yeosang slipping out of your cave earlier.” Catching the look San was twisting his face into, he added, “not too early. Just a little before I decided to tidy up for the day.”

After a moment, San just nodded. “Thank you, Seonghwa.”

“Have a good day, San,” Seonghwa said, flapping a hand at him.

Needing no other encouragement, San swam off.

–––

Wooyoung woke slowly, feeling far more warm and coddled than he had expected to. Yeosang had left earlier, he was pretty sure. He hadn’t really woken up, per se, but he’d been at least a little conscious. So it made no sense that he felt like he was tangled up with another person. Even if he’d dreamt the whole Yeosang thing – which he was pretty sure he hadn’t – San wasn’t a late sleeper, preferring to get up and get going, either laying fishing lines or checking them.

“You’re thinking awfully loud,” San said, the trill trembling against the back of Wooyoung’s shoulder, right where his earfin overlapped the trailing edge of the operculum.

Wooyoung shivered, his eyes falling shut once more. With a low purr of appreciation for the sweet sensation, he twisted against the kelp-and-rope netting, rolling so that San’s long bulk covered him better, so that their tails were twined together in a roil of red and deepest, darkest green, San’s pale skin pressed close enough to Wooyoung’s back that he could  _ feel _ the whisper-fine skin over his gills moving as he breathed.

San made a low, hungry noise, suddenly tightening the grip of his tail against Wooyoung’s, though his hands, settled around the other mer’s ribs, remained carefully loose, his talons flexed out instead of in.

Grinning, Wooyoung rolled his head back, so that the length of his throat was bare and the curve of his skull nestled into the curve of San’s shoulder, like they were designed to fit together. Perhaps they were. Wooyoung hadn’t met many sirens, hadn’t particularly liked any until San. But San...San enchanted him in ways that no other mer he’d encountered could, and it went well beyond his gaze and his song.

“How many times,” he murmured, not bothering to open his eyes, “do I have to tell you?” 

The wounded, punched out sound San made was well worth the effort of working his hands down, until they were sitting on top of his mate’s. Wooyoung wasted no time in taking another deep breath, twining his fingers with San’s, and pressing his hands, sharp-edged talons and all, into his skin.

“My gills,” Wooyoung reminded San silkily, “are in my throat, not my hips. And I like it when it hurts a little.”

–––

Hongjoong scrubbed his hands nervously over his thighs, seated on the side of the boat. The ocean stretched out before him, a glittering wash of dark and light in constant motion, but that wasn’t what he was watching. He only had eyes for the waves lipping nearest the boat, the ones that could easily be hiding the dark trail of a siren on the move.

Wooyoung would be harder to hide, he knew. Where most mers in this part of the world had darker tails, with color splotching up their backs and, occasionally, to their fingers and faces, Wooyoung hailed from a warmer part of the world, where a bit more color was more common. His ancestors hadn’t been hiding among the rocks; the rich crimson of his tail and its darker red and black freckling were perfect for blending in with reefs. With sandy-pale hair and darker skin above his scales, Wooyoung often stood out among mers from the northern waters.

A ways out, a figure popped up from the water. 

“Looking for me?” San called, voice projecting clearly across the space.

“Should’ve been looking for me!” Wooyoung said, surfacing on the other side of the boat, away from where Hongjoong had been looking. 

Mingi yelped, clearly surprised by the sudden appearance of a mer from the opposite direction of Seonghwa’s pod grounds. Wooyoung’s incredibly thick accent when speaking Korean, plus the lisp around his teeth, probably didn’t help.

Hongjoong sighed. Had he really expected anything else from this pair? As he waved to San, urging him closer, he told Mingi, “Go ahead and put your in-ear in. Also, Wooyoung and San are agents of chaos, no matter what they try to tell you. They once spent four months herding dolphins over a 30 mile stretch of ocean, just to screw up the data the NOAA was trying to get.” 

“To be fair,” Wooyoung started, rolling onto his back to catch the throat-mic and earpiece that made up a translation collar from Hongjoong, “they were listening for ocean sounds.” He started working the equipment in place, at the same time slowly flexing his tail, so that he drifted around the side of the boat.

“Ocean sounds does not mean ocean creatures singing choruses of Beyonce,” Yunho yelled from the helm. 

Mingi, wide-eyed, looked like he wasn’t sure he could trust what he was hearing.

Fair enough, with San and Wooyoung, Hongjoong figured. “Different dolphin pods ‘speak,’ if you will, in different tones and pitches. Four months of data, sped up appropriately, sounds an awful lot like ‘Single Ladies’.”

Wooyoung’s expression – a mimic of a human grin – was far too much for a mouth with that many sharp teeth. “Four months worth of data, sure. But how long did it take us to find and move that many dolphin pods?”

“Far too long,” San said, finally surfacing beside his partner. Unlike most mers, he spoke Korean with no problem. He rested his arms on Wooyoung’s flat belly, then beamed up both humans looking at him from the boat. “I said we should just have some really noisy sex, but this one wanted something clever.”

“There’s enough mer sex on ocean recordings, anyway,” Hongjoong said, making a face. He turned to Mingi. “Mingi, meet Wooyoung – mer with the red-pepper tail – and San – siren.”

San waved, still leaning casually on Wooyoung. He didn’t even seem to notice when the other male twisted and sank, though he must have, because his arms dropped loosely around Wooyoung’s shoulders as he shifted to be upright, as well.

“I always love hearing how humans describe my coloring,” Wooyoung said, waving as well. “Red pepper. Sounds fancy.”

“It refers to the darker red and black speckling,” Mingi said, helpful. “Seonghwa-hyung is, what, salt? Salt and pepper?” He directed this last bit at Hongjoong.

But Hongjoong shook his head. “It would be blue salt and pepper, or even just blue salt, if it were true white.”

San made a playful sound in the back of his throat. “Ahh, it’s different because he’s sparkly!”

“Shiny,” Wooyoung corrected.

“Actually, shimmery,” Hongjoong replied, reaching up to pinch the bridge of his nose, “at least to human eyes. A colorshift we call pearlescent. Because of that, he’s actually…”

“A blue starlit?” Mingi asked.

Hongjoong nodded, grimacing at the over-romantic names humans applied to mer color patterning. To be fair, mer terms for their patterns and shades were often equally as maudlin, but there was something about referring to his husband’s tail as “blue starlit” that just… Yeah.

San curled his tail up, twisting so that at least part of the long stretch could be seen above water. “What’s my fancy name, Hongjoong?”

“Green,” Hongjoong said flatly. 

Mingi, though, leaned in a bit. “Pardon, but is your tail completely the same shade?”

San nodded. “There’s some minor shifts in tone, like, around here,” he waved towards his hips, “and a bit of coloring you can only see with siren eyes, a bit you can only see with siren or mer eyes, but to humans, yeah.”

“Technically, then, your coloring is called true verdant,” Mingi said. “True any color is pretty uncommon; most mers have some sort of human-visible patterning, even just to break up the silhouette.”

Wooyoung nodded his understanding. “Like fish? So that we’re harder to see from below.”

Hongjoong nodded, as well. “Exactly. It’s a predatory adaptation, and a protective one. Two for one.”

San grinned, bright teeth flashing in the light. “Oh, I know my predatory adaptations,” he said. 

“You would,” Hongjoong said, rolling his eyes.

At the same time, Mingi asked, “ B y that, do you mean you know the ones you have, or the ones sirens and mers in general have? Or that you know about predatory adaptation in general?”

Casually ignoring Hongjoong, San released Wooyoung. Still upright, he let his tail curl and twine beneath him, bringing him closer to the side of the boat where Mingi sat in a smooth, sinuous motion. “Curious, little human?” he asked, tilting his head to the side.

Mingi raised an eyebrow at him, though he was pretty sure the frantic racing of his heart was audible to everyone in the area. “Unfortunately for you, Seonghwa-hyung and Hongjoong-hyung have already told me that they both trust you, so…”

San sank back, his shoulders slouching a little. He tossed a pout in Hongjonog’s direction. “You couldn’t let me scare him even a little?”

Hongjoong just shrugged. “It’s so rare I bring an intern out; the Institute will probably pull my funding if one gets eaten or has a heart-attack because he’s afraid of being eaten.”

“Human,” San informed them both, “is not nearly as tasty as the number of sirens drowning people in the tropics would suggest.”

“Probably our crap diets,” Mingi said, his heart starting to slow now that San had shed his predatory approach. “We’re eating a lot more fat and weird chemical combinations than our ancestors did.”

“Still shameless perverts, though,” San said, wagging a finger at him. “After all, even knowing that an area is full of sirens, people  _ still _ stop for this.” He waved a hand at his own naked, muscular torso. He smiled, teeth safely hidden behind his lips, and then added, “ N ot that it’s not an ego boost, knowing that I’m so hot people are willing to risk death to get a piece of this.”

“And he says humans are the shameless ones,” Wooyoung said in an aside to Hongjoong.

“So,” Mingi said, ignoring his mentor’s laughter. “What can you tell me about predatory adaptations, San?”

“First thing I can tell you,” San said, letting his smile crack open and stretch across his face, “is that only some of them are intended to make luring you in easier. The others make it easier to eat you.”

“So the double dentition?”

In response, San opened his mouth wide, tilting his head back. He tapped one taloned finger against his first row of teeth, bright white and razor sharp, but still relatively human in size and shape. Then, careful, he pointed to the inner set that lay behind them, darker in color and very clearly meant for rending and tearing meat. Before Mingi could say anything, though, he held up his finger, took a deep breath, and stretched his mouth wider.

There was a slick click as his jaw released, and then the lower half of his mouth was sinking forward. San balled his hand into a fist and demonstrated how even that had plenty of room. Then, tugging his hand back out, he made a weird motion, almost like a gulping swallow, and his jaw sprang back up into place. Mouth now closed, San winked.

“That’s impressive,” Mingi breathed, leaning forward a little. “Are the hind teeth naturally darker?”

San shook his head. “We’re hatched with them,” he explained. “As we wean, our parents help stain them. What you use depends on where you are; I’m from the north, so we used a specific type of mud. Other choruses use algaes, kelps, even specific fish or their organs. But you don’t want them black, so squid and octopus ink aren’t actually an option.”

Mingi nodded. “And then the front row come in later?”

“And keep coming in,” San said. “As you can see, they’re a lot less...aggressive? So they’re designed to fall out as they get worn down and blunt. They arrive pretty late – not until we’re ready to start hunting on our own.”

“And when is that?”

“Mid-stage maturation,” San said. “Which is...when it that, for humans, Hongjoong?”

Hongjoong wobbled a hand in midair, squinting. “Developmentally, we’d think of it as towards the end of pubescence, Mingi. Physically able to bear children? But not necessarily safely or healthily.”

Mingi thought for a moment, then made a face. “So...you look mature enough that humans don’t think of you as children?”

San’s grin was vaguely distressing. “Sounds about right, yeah. Though to my understanding, choruses used to send sirens out to hunt on their own as soon as their front teeth were in? These days, you might hunt, but not humans. Other mers, large fish, marine mammals, that’s the usual until you’re a full adult.”

“Humans in recent generations have come to think of childhood as extending longer,” Mingi said, “so that makes a lot of sense. What my great-great-grandfather saw as an adult probably would read as still a child to me.”

San shrugged. “As you say. So, let’s see. Um, my long muscles are a lot stronger than a human’s, and even stronger than most mers. My fingers grow full talons, if I let them.” He held a hand out of the water, letting Mingi see the curving lengths of keratin. “It’s not uncommon for sirens to blunt or sand our talons down,” he admitted, “because our parents teach us pretty early in hunt-training that it’s off-putting to have claws. Useful, though, so some of us just learn to keep our hands hidden.”

“Hunt-training?” Mingi asked.

Wooyoung snorted. “What, you think mimicking humans is as easy as seducing them?”

San batted a wave of water towards his partner. “He’s not wrong,” he told Mingi. “Older sirens teach the younger about...well, about our prey. Humans, other mers, where to find what kinds of fish, how to separate seals from their pods, how to drown a dolphin, so on and so forth. Where did you think I’d learnt Korean?”

That took Mingi aback. He spent a moment just blinking, clearly thinking through the implications of that statement. “Sirens...sirens are a lot more prevalent than we humans like to think, aren’t you?”

San’s grin was pure mischief. “Oh, father of the waters, yes.”

Mingi’s eyes narrowed. “How prevalent?”

“No one knows for certain,” San sing-songed. “But I will say...Seonghwa’s isn’t the first group that calls itself a pod I’ve lived with, when I left my natal chorus. It is, however, the first that  _ humans _ would call a pod. If they knew.”

Hongjoong watched Mingi carefully as the penny teetered, tottered, and then dropped.

“There are mer pods...that aren’t…”

“Aren’t, genetically, mers, yes,” San said, nodding. “I mean, give it a few generations, and it starts to mix out, but…” He straightened up, gesturing at his own hips. “Let’s just say, any time you meet a mer who breathes near their gut, you’ve a good idea where at least part of their family comes from.”

Mingi went a little pale, thinking about some of the mers he’d known when he’d been studying in the tropics, including one juvenile female who had struggled to learn to breathe at the surface, because her gills, hidden in the swirl of the fins located on her hips, couldn’t just be pinned down the way her cohort taught themselves to air-breathe.

He’d thought it a birth defect, of sorts, at the time, but now…

“Mm, that’s the other thing,” San continued, stretching out in the water so that he could point to his hips. “Our gills. They’re pretty small, and pretty well hidden. We don’t have any kind of covers, because those might let whoever’s looking at us know they’re there. And humans just don’t have gills.”

“Or sit on rocks along the coast in the dead of night, usually,” Hongjoong put in dryly.

“Ah, but as long as they’re telling you to come fuck them on the rocks, some things can be forgiven,” San shot back. “Being obviously fishy is a no-go, though.” He eyed Hongjoong, then added, “ F or most people.”

Hongjoong treated him to a rude gesture.

–––

After spending a good hour talking about the differences between mers and sirens, with Wooyoung and San cheerfully indicating differences on their own bodies, Mingi had easily turned the conversation towards his research. Seeing him well-settled, Hongjoong had withdrawn a little further along the deck, pulling out the recordings from earlier in the season and making sure that the automatic translations were accurate. From time to time, he also added bits of nuance or notations about slang. It wasn’t the most fun part of his research, but it was critical. Language use and development among mer pods was just as unique and messy as it was among landside humans, and, just as with humans, research as a whole required being able to communicate with one another. 

He was glad that Mingi was getting along with his pod; they were good people, and he’d been drawn in by Mingi’s easy kindness in the labs. Seonghwa and his pod-members were pretty far from the usual for mer pods, but Mingi hadn’t let that shake him at all. Beside the initial freakout over the fact that he was going to come face to face with a siren, Mingi hadn’t seemed bothered or disturbed by the patchwork nature of Seonghwa’s pod. 

Which, to be fair, was more than Hongjoong could say of some mer pods. Seonghwa’s pod was based less around blood families and far more around the chosen; where the average mer pod tended to have three to four primary bloodlines represented, Seonghwa’s varied with the season. Most mer pods crossed bloodlines across their clans and communities, binding the whole group together over the generations, but Seonghwa’s pod was, in essence, a messy knot created by several of those crossovers and their outlying connections.

Seonghwa was the only one native to the area. His natal pod had lands a good thirty leagues away, which was a full, energetic day’s swim from where he lived with his own pod. His mother was pod-head, and had been for most of Seonghwa’s life. His father hadn’t been very present in his life, as an attache to one of the community’s heads, but Seonghwa had spent a few seasons traveling with them and getting to know the local pods and clans that made up the full community.

He had followed one of the other assistants working with his father in establishing a pod where they had; Hyorin had been tired of the life of swimming and wanted a central place to live and have children. She’d brought a few hunter- and guard- mer with her, people who didn’t fit in with their own pods or who wanted a bit of a change. Seonghwa had thrived within that group, bringing in others he had met over the years who had been looking for somewhere else. 

One of those had been Wooyoung. Wooyoung’s father had met his mother one season while traveling, and they had rejoined Wooyoung’s father’s pod after they married. Wooyoung had always stood out as being more Southern than most of his pod-mates; his coloring was brighter, his overall size more compact, and his song shriller. His pod had also been almost exclusively craftspeople, in a clan where each pod had their own focus to support the clan as a whole.

Wooyoung, while swift of hand and talented at working with both seaweeds and surface fibers, had never really wanted to be just a craftsman. He’d been far more interested in helping to hunt, and in exploring the ocean around them. But he’d been too small, per the guidelines of the hunting pod, and too bright, according to the scouts. So when Seonghwa had asked him if he wanted to join the pod he was in…

It wasn’t long after Seonghwa had been named pod-head by Hyorin (who was retiring to her sister’s pod, to help her sister raise her children) that Wooyoung had seen a young siren lurking on the outer edges of the pod’s territory. He’d told Seonghwa and the captain of the guard about it, how the siren was small – clearly young – and far too thin. The siren hadn’t menaced him, hadn’t approached at all, but it also hadn’t fled far when he swam past. 

Seonghwa had armed himself and swum out with the guard, ready to warn off whatever threat the siren chorus had sent to them, only to find a half-starved, very-battered siren that had immediately begged shelter.

San – so the siren had identified himself – spent more than a month securely bound in a small cave that the pod used as a prison, being tossed fish and shellfish, answering the questions put to him. Initially, they had tried to feed him some of the sea greens they harvested regularly, but after that left the siren writhing in pain and vomiting, they’d come to realise there were reasons that sirens didn’t bother with vegetation. It cut into the pod’s stores of fish, but they kept the siren fed as they pulled the information from him.

He’d sworn oath after oath, let the guards and healers sand down his talons and his front teeth, even let them bind up his head so that he couldn’t extend his jaw to the fullest. San wanted to live a different life than the one he’d been born into; he didn’t want to hunt sentient beings, barely wanted to hunt large mammals unless they were threatening his people. He was aware how much work it would take to keep up with his nutritional needs – had tried and failed to do it alone – but was willing to throw in with the mer pod to hunt larger fish, to put his skills and abilities to their use, if only he didn’t have to be all alone in the ocean any longer.

Wooyoung had watched him the way an octopus watches a fish among the coral, constantly on guard for the siren to snap, or to lash out. Eventually, though, he’d stopped tailing him and started joining him, then talking to him, and then he wasn’t watching him so much as spending time with him. 

It’d been San who found Yeosang, originally. He’d been on a long-ranging patrol, swimming along the distant edges of the territory, and had seen a dark streak. He could smell the blood in the water, but it had been dilute enough that even he, with a predator’s keen senses, couldn’t track where it was coming from.

Tracing the very boundary of the pod’s waters had gotten San close enough to recognise that there was a body floating in the midwater, but that was it. He’d streaked back home – he had a  _ home _ ! – and let his pod-head know.

Seonghwa had taken his report, a curious look on his face. After briefly conferring with his heads-of-guard, Seonghwa had taken a small group of guardmembers out to where San had seen the floating form.

It had drifted, some, on the current, and sunk a little further in the water, good signs that the person was dead. Still, Seonghwa had kept his knife out, ready to strike, as he approached.

Yeosang had been little more than shreds of a mer, his flukes and thinner fins hanging in tatters, his flesh torn and ragged. He wore no adornments, no tokens of any kind, though it was clear enough where they had been. His gills had fluttered weakly as the water around him swirled, stirred by Seonghwa’s movement, the sole sign of life.

No one had been more surprised than Yeonjun, the pod’s healer, that Yeosang had survived. That he had worked his way back to fighting fit, and better, had seemed to surprise the healer less. 

After all, after a fight like that just to live, everything else must have seemed simple.

–––

Jongho sat happily on the swimdock at the rear of the boat, talking to Mingi as he took advantage of a stable surface location to give his tail a deep grooming. He was leaning against the rear wall, his relatively short tail curled up towards his body, flippers fully flared. Using his fingers, he was brushing through the fur, identifying rough patches or spots that, as he put it, “didn’t feel right.” Those, he attacked with full fervour.

“It’s a little odd,” he admitted, “being intended for a much colder climate. Like, I’m definitely meant to be bulkier than I am.” Releasing one flipper, he waved a hand at his densely-muscled, stocky torso. “And when it gets colder, I gain weight super-easy. Like, my face gets all round and I start packing it on. But never as much as when I lived way north.”

Mingi nodded, watching him work through his tail, half-heartedly working on checking his own equipment. “And in the summer? Do you overheat?”

Jongho twisted, resettling himself. “It never really gets too hot, at least not out here. Like, if I swim in towards the cove, in the real shallow water, on a sunny day? It’s warm, and sometimes a little too warm. But that’s not common, because we’re far enough north, and the currents are running from cooler waters. I’d probably be real bad off in the tropics, though.”

That got a grin from Mingi. “That’s where I did a lot of my research for my doctorate,” he said. “Definitely did not see many mers with fur, there.”

Nodding, Jongho pulled one flipper closer to himself. As he dug in between the bony lengths of his tarsals, he said, “ S cales?”

“Scales and skin, yeah,” Mingi said. “Lots of colors, most of them bright. Plenty of sparkle, and patterning like you wouldn’t believe.”

“Seonghwa met some of the southern mers at a cross-community event, once,” Jongho said. “He said they were really fancy looking. And they had really pretty coral jewelry.” He sighed, tail twisting under his hands and sliding free.

Mingi flinched away from the splash of water. “Definitely lots of corals and colors,” he agreed. “A lot less wood used than up here, though. Things there tended to be shaped from coral and stone and such.”

“We do some stonework, too,” Jongho said. “Like, Soobin and Beomgyu do a good amount of stone-shaping for our pod. They hollow out caves, and smooth out the ones that are already there. Get them ready for people to live in, if they like cave nesting. Or they shape out the nice units, too, for people like Seonghwa.”

“Like Seonghwa?” Mingi asked, cocking his head.

Jongho nodded, even as he stretched back and then rolled to lie on his belly, tail stretched out, flippers idly flexing where they dangled in the water. He huffed happily, sealing his nostrils and eyes shut for a moment, then craned his neck to look back in Mingi’s direction. “Ugh, I love days like this,” he said. “Yeah, Seonghwa doesn’t sleep in caves, or under shelter, really, unless there’s, like, a massive current coming through or something. He tethers himself to the kelp and sleeps like that.” He gestured in midair, drawing a vertical line with a flat hand. “Couple of the others are like that, too. It’s kinda creepy if I’m getting back in the middle of the night, you know? People just...hanging there.” He shuddered.

Mingi made a face, coming closer to the edge of the boat so that he could see Jongho better. “Yeah, I can see that.” Eyeing the way Jongho had his head laid on his folded arms, he asked, “You need to be back by any particular time?”

“Nope,” Jongho said, shaking his head. 

“Cool, then,” Mingi said. “Enjoy your nap.”

–––

Yunho wasn’t sure, at first, what he was hearing. He’d all but grown up out at sea, on the fishing boats his parents owned, and so he’d long been used to the sounds that ships made throughout the day, and how they sounded in the dark of the night. He’d been working with the Institute and with Hongjoong long enough to even have learned some of the sounds of the ocean’s inhabitants, like the singing chirruping roll of Seognhwa’s mermish, or the liquid, silky way San’s voice resonated, practically rippling through your blood, when he spoke.

But what he was hearing…

Screaming. He would have called it screaming, except that something didn’t feel right about that description. Screaming was sharper, shriller, more  _ human _ . And while these sounds were piercing in their clarity, ragged with the edges of pain and panic, there was something almost song-like to them. Something inhumanly perfect, impossibly smooth.

“Yunho!” 

He all but fell from his bunk, hearing Hongjoong calling his name. He didn’t think he’d ever heard that particular tone in his hyung’s voice, but it was already sending sharp spikes of alarm through him. Heart pounding, Yunho bolted from the tiny closet he called a room, stumbling towards the deck where he’d heard Hongjoong calling from.

“Hyung?” he demanded, tripping over his own feet as he made his way up the stairs to the open-air decking. “Hyung, what’s going on?”

Hongjoong was whey-faced and frantic, his eyes dark pits in his face beneath the moonlight as he scrabbled at the cabinets where they stowed the dive gear. “Something’s going on,” he said, finally getting the door to swing open for him. “Can’t you hear it? I need...Seonghwa needs…”

“That’s the pod?” Yunho asked, his heart tripping even faster. “That sound?”

Hongjoong nodded, yanking out his flippers and air hoses. “Do we still have the dive guns?”

“We do,” Yunho said, heading towards the tidy nest he had at the helm. “Should I bring us closer?”

“No,” Hongjoong said, checking his mask quickly before yanking it over his head. “The sound of the engine will throw Seonghwa’s pod off. I just need to get in the fucking water!”

“Steady on, hyung,” Mingi said, coming up from belowdecks. With his long legs, it took him no time to cross to where Hongjoong was struggling with the tangled straps that held his air tanks in place. “What’s going on?”

While Mingi worked on getting Hongjoong straightened out, Yunho took the key that lived, unused, on his keyring and opened the safe that sat behind his chair. The wall panel folded forward, and he removed the spear gun that he put there at the start of each season, as well as the mesh bag of spare spears for loading it. Unlike spearguns designed for fishing, this one had no tether leading back to the gun, and the spearheads were flanged and wicked. It was designed for danger, and the only reason they carried it was for protection. They’d never needed it before.

“Seonghwa’s pod is under attack,” Hongjoong said, letting Mingi check his air tanks for safety. “They’re the only pod close enough for us to hear the screaming. And that’s screaming we’re hearing.” 

“Hyung,” Yunho said, reaching the deck once more. He held the gun out to Hongjoong. “Let me tag you?”

Hongjoong paused, hand still outstretched for the spare spears. After a moment, he nodded. “I’ll carry the communicator,” he agreed.

“Thank you, hyung,” Yunho said. Reaching behind Mingi, he snagged one of their ping-enabled communicators, then hooked it in to the webbing at the front of Hongjoong’s harness. “You need us, you call us. I’ll launch the dinghy in a heartbeat, you understand me?”

Hongjoong nodded. “Yeah, Yunho. Thanks.” he turned to Mingi, nodded again. “Thanks, both of you.”

Yunho stepped closer to Mingi, pulling him out of the way as Hongjoong launched himself over the edge of the boat. The pair of them watched as the man worked his flippers on in the water, turned his oxygen on, and then, after a brief OK sign, dove beneath the water.

“Now what?” Mingi asked, looking a little frantic himself. 

Yunho couldn’t blame him. The sound, now identified as mermish screaming, hadn’t stopped. He could feel the hair on the back of his neck standing on end. Still, Hongjoong had said that bringing the boat closer would cause more harm than good, so, as so many times in the past, he would wait.

“Now,” he told Mingi, clapping the other man on the arm, “we grab my radio and go to the kitchen. Coffee, my friend. Lots of coffee.”

––—

Yeosang both cursed and blessed the lungs on his friends; San’s rippling, warbling scream could be heard through every inch of the pod’s waters, and that meant that the children and other non-fighters had heard him. That meant that Yeosang could trust that they were safe; they would have retreated to the reinforced maze beneath the cliff at the first sound of alarm. It was late enough in the season that there were no egg-cases hanging on the kelp or hidden in the sands; everyone in the pod could withdraw to safety. Soobin or Beomgyu would likely be standing by, waiting with one of the warriors tasked with guarding the pod, ready to drop the gates that would block off the caves.

That meant that he could bolt from within his own cave, buried deep at the edge of the kelp, shedding sheathes as he went. He wore his bandolier of knives, and armed himself readily with one of the wicked spears from the guardhouse. The twining ropes holding the stronger sheathes in place dropped easily, strands parting beneath a single clawed strike. The heady kick of his tail tossed the rest, leaving razor sharp glass and stone waiting.

Whoever was attacking his home would regret it, Yeosang vowed, swimming faster for the darkness that was already singing with the stink of blood.

–––

Drawing back to try and catch his breath – and to staunch the blood leaking from the gash on his ribs – Wooyoung watched the fighting from just above where the sea floor became a cliff, plummeting into nothingness. He could barely keep track of his partner, but he knew San was out there, a wild roil of fangs and talons in the dark. He was smaller than the other sirens, but with everyone moving as fast and messily as they were, that wasn’t any kind of help. Wooyoung knew he had to rely on San’s familiarness to keep him safe from their own pod.

But San knew how the pod hunted, knew how they fought, and that would stand him in good stead, Wooyoung was sure. He had to trust in that.

Yeosang was also fighting, twining and swirling like the venomous sea snake his tail resembled. In the dark, the bands of white and gold were muted, but he was still easy to find. Just follow the billowing clouds of blood, and there was Yeosang. With a short knife in one hand, the long spear in the other, and blades at his hips, down the length of his tail, and even along his flukes, Yeosang was one of the few mers who could take down a siren on his own. Add in the fact that he wore venomous spines around his gills, so that no siren dared go after them, and the fact that he’d been born into a war pod, and Yeosang was very nearly the most dangerous thing in the water right then.

Wooyoung watched as Yeosang rippled and rolled through the tangle of encroaching sirens, leaving a trail of bloody, struggling bodies behind him. In his wake, others descended, taking advantage of the damage already done to drag the sirens down.

As he watched, Yeosang seemed to hit a knot he couldn’t sever; a horrible screech tore through the water as blood billowed forth.

Not even thinking of the still-stinging edges of his wound, Wooyoung shot forward, stealing a loosely-held blade from the struggling siren he passed on his way.

–––

_ Oh _ , Yeosang thought, distant, tired.  _ It’s okay. Someone else will take care of the babies. _ He wasn’t sure who, or how they’d found them in the little cave, but he could hear someone with a deep voice chanting, “no, no, no.”

He didn’t know who it was, but they couldn’t be as bad as Minsoo. Not if they could sound that upset without being angry. And he certainly didn’t blame them for being upset; the kids barely had the muscles needed to swim, too underfed and weak to do much more than bob in place. Depths, Yeosang himself barely had the body fat to stay warm, and if he’d been any younger, his muscle likely would have withered away, too. As it was, he knew that he had to look just as hollowed out as the kids he’d been protecting.

How had Minsoo’s men found them? They’d never been great trackers, and he thought for sure he’d managed to get far enough.

_ Should’ve known _ , Yeosang scolded himself, letting his eyes slide shut again.  _ Needs his sacrifices. _

He could feel his body moving through the water, moving and bobbing through no effort of his own, and he wondered if they’d found a current to cast him into. It’d be nice, a final mercy, of sorts. He didn’t want any of the kids to see him dead; they’d probably seen enough, after Minsoo’s men had finished with him at the mouth of the cave, and they’d been pulled out.

He could still hear them screaming.

–––

“Shit,” Mingi hissed, looking at the dark smear staining the water that he and Yunho were frantically motoring towards. Hongjoong had said to bring the medical supplies on the ship, but Mingi was starting to think that those might not be enough. There was an awful lot of blood visible from here, and if he could see it on the surface…

At least Yunho had thought to throw more dive equipment, including air tanks, in the dinghy before they’d launched. Mingi had been an EMT in college, and through grad school; he’d done some marine medical training, too, during his initial rounds of post-doc. He’d never treated a mer before, but he had no qualms with lending the pod’s healer a hand.

Jongho bobbed to the surface as they got very near where Hongjoong’s GPS was pinging, noisily blowing water from his nose. “Hongjoong says you better have brought the backboard,” he announced.

“We did,” Yunho said. “How bad is it?”

“Bad,” Jongho said. “Siren attack. Yeosang looks almost as bad as when San found him.”

Mingi’s heart was racing, a bruising tattoo thudding against his ribs. “Yeosang?” he asked, taking the pieces of the collapsible backboard that Yunho handed him and fitting them together.

Jongho huffed another breath, clinging to the side of the dinghy. “He was born to a war-pod,” he said, “and they were threatening his children.”

Leaning closer, Mingi eyed Jongho closely. “Are you injured, or just exhausted?” he asked, getting a good look at the mer’s pale face.

“Mostly exhausted,” Jongho said, slumping against the dinghy’s inflatable side. “Just small injuries...they’re already closing up.”

“Not actively bleeding?” Minho asked.

Jongho shook his head.

“Alright,” Minho said. He’d forgone most of his wetsuit, having neither the time nor the space to get in his full gear right now. Instead, he was trusting his wetsuit jacket with its beavertail, and the adrenaline racing through his veins, to keep him warm while he was in the water. Once he was out, he knew he’d be cold, but Yunho had fleece blankets aplenty tucked into dry sacks, and multiple thermoses of hot tea and coffee.

Double-checking the sit of his air tanks and his flippers, Mingi fitted the mouthpiece of his regulator in place. He shot Yunho a nod and an OK, then rolled backwards off the side of the dinghy and into the dark water.

–––

“I’m going to have Yunho bring our boat closer,” Hongjoong told Seonghwa, rubbing his hands up and down the mer’s upper arms. He was swimming close to him, tail fins and flippers stirring the same strokes of water. “The younglings are all in the caves?”

Shaken, Seonghwa nodded. His dark eyes were wide in a pale face, and the frilled fins along his ears were fluttering frantically. His gills were moving quickly, too, trying to keep pace with his speeding heart.

Not that Hongjoong was much better off; he knew that he’d be having nightmares of sharp-fanged maws appearing from the darkness below him, of Seonghwa vanishing behind inky blows of blood, of bubbles pouring from a man-like being’s side as he sank. But for now, Seonghwa needed him, needed access to the resources and technology Hongjoong had as a human, for healing and protection. He needed Hongjoong to be steady for him, and so Hongjoong would hold back the panic.

Impulsive, he leant in and brushed a soft kiss against the high arch of Seonghwa’s cheekbone, blowing a stream of bubbles from his nose as he did so.

Seonghwa answered instinctively, a sweet  _ chrrr  _ rolling up from the back of his throat. Nudging Hongjoong’s cheek with his own nose, he offered him his own ticklish stream of bubbles, and then a long, slow kiss. 

They hung there, for a moment, two beings amidst the chaos of the sea, hearts finding pace with one another, Seonghwa taking advantage of his gills to breathe for the both of them. All too soon, however, the mer was breaking the kiss, pulling away. He studied Hongjoong’s pout for a moment, then gave him another quick kiss, this one chaste.

“You need to go,” Seonghwa told Hongjoong, unfolding his arms to let his fingers tangle with the man’s. “You’re just using your back-up.”

Hongjoong made a face. “Come up with me,” he urged. “Make sure we anchor well. I’m not leaving you alone after that.”

But Seonghwa shook his head. “They need me here, love,” he said. “I’ll send Wooyoung up with you. Tides know he’ll follow, anyway; Mingi took Yeosang up to the top water as soon as Yeonjun said he was stable enough.”

Sighing out a plume of thin bubbles, Hongjoong squeezed Seonghwa’s hands once more. “I’ll bring them back down soon, Hwa, I promise. And I’ll be down again, too.”

“I know,” Seonghwa said. Releasing Hongjoong’s hands, he waved to him. “Go on, then. Before you need medical attention, too!”

With a nod of his head, Hongjoong tucked his octopus regulator into his mouth, his tiny temporary air bottle the only one left in his rig. Blowing a kiss at Seonghwa, he began kicking his way back to the surface.

–––

“Does your skin handle seawater better than human standard, hyung?” Mingi asked, peeling off his wetsuit with a disgusted look. He reached for the medicated cream that Yunho had taken to leaving at the edge of the wetsuit storage, pumping out a generous handful and starting to massage it into his white, dead looking skin. 

Hongjoong looked down at his bare chest, where his skin was as healthy and tan as ever. To be fair, he had not spent nearly as much time in the water as Mingi had, recently; his intern had been in the water near-constantly for the past day and a half. Still, he’d been under (and in and out) often enough that he thought he would see some effects, if he was going to.

“Apparently not?” he offered. “Which means you’re going to crash course me through what you’ve been doing for Yeosang; we can’t afford for you to be getting salt water dermatoses right now. Or ever, really.”

Making a face at the thought, Mingi peeled off the rest of his wetsuit. “Yeah, not a thing I’d like to experience,” he said. Bare as the day he was born, he carried his sopping wetsuit to the open air line they’d set up and clipped it into place, to let it drip out a bit. Then, snagging a towel, he began to pat himself dry. “How confident are you in your basic medical skills, hyung?”

“Define basic,” Hongjoong returned.

“Pulse, breathing check, wound management,” Mingi rattled off, ticking things with his fingers. “I’ve been doing a bit more, but Yeonjun’s got an apprentice, he said. One of them could probably handle some of it, if you’re taking on some shifts.” He yawned, winced, then reached for the medicated cream again. “Because I might need to get out of the water.”

Hongjoong frowned, seeing the way dead skin peeled off beneath Mingi’s hands. “You do,” he said. “You really, really do. Dry out a little. Get a good wash under freshwater. Dry out some more.”

Mingi paused, looked at his towel, then looked at Hongjoong. “Alright,” he said. “Get over here. Let me make sure you’re up to my standards.”

––––

“Come on,” someone was chiding. “Let me see those pretty eyes.”

Yeosang whined, shifting against whatever hard surface he was lying on. His eyes felt tight, as stiff as the rest of him, glued shut. He tried to lift a hand to swipe at them, but something along his arm stung, and he flinched, instead.

“Oh, you’re okay,” another person said. 

There was a sharp pinch, and then he could taste the blood filtering through his gills. Barely enough to comment on, but he knew it had to be his own, and he wasn’t much a fan of that. Yeosang whined again, starting to shift more aggressively.

“Hey, hey,” the first someone said, “you’re going to hurt yourself, Yeosangie. Open your eyes, first. Then we’ll see about the rest.”

“Where…?” he managed, even as he struggled with the gluey sensation around his eyes. They were starting to crack open; he could see threads of light.

“We’re in the top water,” another voice answered. This one had a thick accent, nearly impossible to understand. Like he wasn’t used to speaking. “You’re okay.” And then he spoke again, this time in a language Yeosang didn’t know.

“We’ll let you off the backboard,” the second voice said, “if you think you can move enough not to need it.”

“Negative buoyancy’s a bitch,” the first person – San, Yeosang realised – said, sharp-edged grin clear in his voice. “You’re gonna be wearing some human clothes for a while; you tore one of your compression muscles.”

Yeosang finally managed to get his eyes open enough to see faces around him. They were blurry, but there were three of them. One looked odd, though, shiny and black in an odd pattern, like a bubble trapped by an intrepid octopus goofing around. He squinted, though that didn’t really bring anything into focus.

Another burble of foreign language.

“Mingi says to tell you that he’s here,” San said. “You remember Mingi, yeah?”

“Min...gi…?” Yeosang wheezed, feeling the sudden surge of aching as he breathed. Oh, torn compressor was clearly the least of his problems. He felt like he’d been used as a whale’s snack. 

As he moved, though, flexing his muscles, feeling the responses, delayed and painful as they might be in a few places, he could feel his brain starting to move more quickly, too. “Mingi,” he repeated. “Why’re you...sirens!”

Hands grabbed him as he flailed out, and, amidst the surge of agony that washed through him, Yeosang was grateful for their support.

“You’re okay, you’re okay, you’re okay,” Yeonjun was chanting, his hands firm on Yeosang’s side, as sound and the world eased back in.

“I’m,” Yeosang gritted, “okay.”

“You are,” San said, on his other side. “Mingi just said that, uh, you might not want to move too quickly, for a bit.”

Only knowing how bad it would surely hurt kept Yeosang from laughing at the understatement, which he’d come to know as being classically Mingi. “We won?”

“We won,” San agreed. “You were the worst hurt. Hongjoong brought a speargun, and let me tell you, that human phrase about bringing a knife to a gunfight? Exists for a reason. We’re running double patrols, and Seonghwa’s had Hongjoong bring his boat right into our podlands. Wooyoung swum the anchor down himself.”

Mingi said something, then looked to San for a translation.

Yeosang did, too.

“Mingi said that he and Yeonjun and Hongjoong have been keeping an eye on you,” San said. “Making sure you kept breathing, kept floating.”

Mingi still looked nervous, beneath the shine of his full-face mask, so Yeosang carefully stretched out an arm to him. It took a moment, but Mingi swam a little closer, then carefully, so carefully, wrapped his fingers around Yeosang’s hand.

“What all is wrong?” Yeosang asked. He tightened his grip on Mingi’s hand, just a little.

Yeonjun snorted. “Faster to name what isn’t,” he said, then dove in to his recitation. “Torn compressors, as San mentioned. Your swim bladder was punctured, too, in the same stab. It’s healing quickly, but you’re going to be struggling with buoyancy for a while. Mingi’s loaning us a dive vest, which you can inflate or weight as you need, but I want you staying near the top or midwater for a good while, even after you don’t need it.

“You lost a good amount of blood, between the stab to the side and the damage to your tail. I’ve stitched your flukes back together –  _ again _ – and I’m going to go ahead and tell you that you’re going to be missing scales for a few seasons. Also, if you want those damn fin blades back, you’re going to get to enjoy getting them redone, after your fins finish healing. As it is, at least one of your ventral fins may not heal enough to allow it.”

Well, that certainly explained the feeling like he’d been shredded; he had been. Yeosang nodded slowly. “Okay.”

Yeonjun’s expression was sour. “You also have two broken opercula, one of which is stitched back in place, and we’re all hoping it heals properly, because that’s a new repair for me. On that note, your throat – inside and out – is bruised, so I’m also advising that you avoid surface breathing for at least the next week. It’s going to hurt like anything.”

“Got it,” Yeosang said. “But...nothing too permanent?”

“You have a disgusting definition of not permanent,” Yeonjun told him. “But, no. You will heal, albeit slowly, and painfully, and probably with an interesting setback or two.”

“As long as I do,” Yeosang said, closing his eyes. He leant back against the stiff surface, feeling it bob. Ah; they had somehow floated it, then.

A low chuckle – Mingi’s? Definitely Mingi’s, washed as it was through the mask. Yeosang felt him release his hand, and felt a surge of loss.

“Get some sleep,” San said, feathering his talons through Yeosang’s hair, the way he had so many nights before, when every moving shadow was a mertail on the hunt. “We’ll be here when you wake up.”

Yeosang, already drifting off, mumbled, “I know. Trust you.”

–––

“Hyung,” Mingi said, staring out across the water. In front of him, a plate of stew waited, still steaming, fresh from the pot. “D’you see that?”

Hongjoong, frowning, followed Mingi’s gaze. “See what?”

“That,” Mingi repeated. Setting down his spoon, he pointed. “Out a ways. It’s...something.”

Hongjoong frowned, squinting. He leant forward, then turned to look at the third person seated at the table. “Do you still have those night-sight goggles at the helm?”

Yunho nodded, already rising to his feet. “Yeah. Hang on.”

They waited, impatient, staring out at the darkness, trying to see the shadowy void in the night that Mingi had noticed. They sat in worried silence until Yunho called from above, “hyung? You’re gonna want to see this.”

–––

“A commercial fishing vessel?” Mingi asked, staring over Yunho’s shoulder. “That shouldn’t be here.”

“We’re only allowed to be here because I had Seonghwa actually sign something to that effect,” Hongjoong agreed, mouth tight and voice dark. “Legally, a commercial fishing vessel shouldn’t be within a hundred leagues of where we are.”

“And running dark?” Yunho said, raising an eyebrow. “Because they are. They’re not flashing basic lights, and they don’t have any shipboard lights going. We’d see it, out here. Hell, they should be able to see  _ us _ .”

“And they haven’t hailed us,” Hongjoong said. He bit his lip. “Wonder if they’re hoping we haven’t seen them?”

Reaching for the radio, Yunho smirked. “I do so love crushing hopes and dreams.” Switching over to Channel 13, he began to drone, “Commercial Fishing Vessel, Commercial Fishing Vessel, Commercial Fishing Vessel, this is the Aurora on Channel 13. Over.”

As Yunho worked to get a response, Hongjoong turned to Mingi. “I need you to dive,” he said. “By our treaty, we need Seonghwa’s say-so to take any actions.”

Mingi nodded. “Got it, hyung.” Grabbing the ladder, he all but threw himself down to the main deck, already heading for the cabinet of wet suits. “Flashlights recharged from last time?”

–––

“Let me get this straight,” Yeosang said slowly, twisting against one of the long strands of kelp in an effort to rub at the incredibly itchy spot where a scale was missing, but the flesh had finally healed. Instead, he let his fingers fuss with the translation collar and earpiece he was wearing, tucked carefully below his still-healing opercula.

“Go for it,” Mingi said, sounding a little amused. He was aimlessly teasing a young wolf-eel, which would dart forth from the kelp, try to nip at his fingers, and bolt back as soon as he moved. 

Yeosang wasn’t sure how to feel about Mingi making a pet out of the creature; he was probably going to have to bring it to one of the groups of younglings to take it in. At least they might learn some responsibility? It might do them good, to have something so gentle to care for. Plenty of the children were still terrified of the dark edge that marked the deeps, the distance of their living area.

“Yeosang?” Mingi asked.

Startled from his thoughts, Yeosang flared his fins...and immediately regretted it. “Fuck,” he swore, a bubble escaping his mouth with the Korean word.

Mingi, who had lurched forward to help him, seemed frozen in mid-movement. Then, after a moment, he began to laugh. It started small, but evolved into a rolling chuckle, which Yeosang answered with laughter of his own. The little wolf-eel, who had darted away at Mingi’s movement, seemed to give them up for lost and vanished into the kelp.

After he had calmed down, Mingi asked, “that’s not your first Korean word, right?”

Yeosang shook his head carefully. “No. I can introduce myself, too. Jongho insisted.”

Mingi narrowed his eyes beneath his mask. “I’m not the one who taught you to swear.”

Again, Yeosang shook his head. “No,” he agreed. “Hongjoong. Speaking of which. The sirens.”

“The sirens,” Mingi repeated.

“They let humans  _ hire _ them?”

Mingi shrugged as best he could beneath his dive gear. “I guess? Understandably, the fishing company wasn’t too chatty about the details of their illegal operation. But it seems, yeah, they had found sirens who were willing to clear out pods, so that they could fish there. Uninhabited lands, and all that.”

“I really hate humans,” Yeosang groused, scowling. Then, turning to Mingi, he pointed at him. “Which doesn’t include you. You’re an intern. Not a human.”

Mingi smiled. “I’ll take it,” he said.

Yeosang watched him for a long moment, and then looked down at his tail. He could see the kelp beneath him washing to and fro, tossed by the backdraft of the tide his tail was shaping. Without looking up, he asked, “would you take more?”

Silence sank between them for several long, long pulses. Yeosang could hear Mingi’s heart speeding up in his chest. He could also hear him clearly trying to calm himself.

Finally, Mingi spoke. “What do you mean?” he asked, placing the words carefully.

“I mean,” Yeosang said, turning his attention to the trail of bubbles streaming from Mingi’s regulator, “Seonghwa asked...asked me to talk to you. To see if...if you might want to join our pod.”

Mingi’s heart picked up again. This time, he didn’t even try to calm himself.

“What about you?” Mingi asked.

“What do you mean?”

“Is it just Seonghwa who wants me to join the pod?” Mingi asked. “Or is there a reason he asked you to ask me?”

Yeosang opened his mouth to answer, then closed it. Opened, then closed. Reaching up to fidget with the edge of his sharkskin cape, he managed a very small, very quiet, “I want it.”

Mingi’s hands catching his on the edge of the sharkskin were startlingly warm; he always forgot how hot Mingi ran, until they touched again. Mingi’s fingers were golden against his own, tanned by the sun and callused from work that was very different from any that Yeosang did. But they wove together easily, folding in on one another, until both of Yeosang’s hands were tangled with Mingi’s, and the human was timing the kicks of his flippers to the pulsing sway of Yeosang’s tail.

“Yeosang,” Mingi said. “I have to leave, for the end of the season. But you...you want me to come back? To the pod?”

Yeosang met his eyes, then said, very firmly, “I want you to come back. To the pod, if you want. But mostly to me.”

The smile that creased Mingi’s face then was more beautiful than any show of light dancing through the water that Yeosang had ever seen, and far more brilliant, besides.

  
  
  
  
  


**Author's Note:**

> Ask me anything about fish biology! And how I'm smooshing it together with mammalian! I SCIENCED this bitch, damnit. 
> 
> But seriously I googled fish penis there is nothing I fear anymore.


End file.
